11 common problems of inaccurate online pH meter measurement
11 problems of inaccurate online pH meter measurement. The common problems encountered in the measurement and use of online ph meters (also known as industrial ph meters) are mentioned below. This article summarizes 11 points and makes corresponding answers. These 11-point questions and answers should help you further your online pH meter use.
1. "E.rr" appears on the screen of the online ph meter transmitter?
Answer: PH is out of range. Possibly: The indicator electrode wiring is disconnected.
2. The number of the online ph meter transmitter jumps randomly, which does not match the water quality?
Answer: It may indicate that the reference wiring is leaking, try to wipe the wiring terminal with absolute alcohol, and keep the humidity at the wiring to meet the technical requirements.
3. The online pH transmitter has no control signal output?
Answer: Check whether the screen is in normal mode.
4. Do you feel that the measured value of the online transmitter is inaccurate?
Answer: Take out the electrode of the online pH meter, clean it and calibrate it according to the instructions. If it cannot be calibrated during the calibration process of the pH meter, please try to replace the electrode.
5. The electrode response is slow?
Answer: When the temperature is low, the internal resistance of the electrode increases and the reaction will be slower. When the bulb is covered by dirt, the liquid junction is blocked by dirt, and the reaction will slow down. Please try to clean the electrode.
6. Does the pH of the electrode remain unchanged in any solution?
Answer: The bulb of the electrode has been broken, and the electrode needs to be replaced. The connection between the electrode and the instrument is off, please check. The electrode cable is internally broken, please replace or send back for repair.
7. For the same sample, the pH values of the two measurements are different?
Answer: The temperature change or the chemical reaction of the sample itself caused the change of pH value. Therefore, try to keep the temperature consistent and avoid chemical reactions.
8. The same sample is measured on two acidity meters (ph meters) at the same time, but the readings are inconsistent?
Answer: Because the calibration conditions of the two acidity meters (ph meters) are different (such as calibration done at different times), the measured values are different. Therefore, the acidity meter (ph meter) should be calibrated at the same time with the same buffer solution, and then measured at the same time.
9. No matter what kind of sample the pH meter electrode is in, the display will not change?
Answer: Because the electrodes are not actually connected to the meter. The treatment method is to turn off the power first, and then reconnect the electrode and the meter. Because the electrode is broken, replace it with a new one in time.
10. The measurement is unstable and takes a long time?
Answer: Because the electrodes are aging. The response time of the electrode in the buffer can be tested. If it is longer than 1 minute, the electrode needs to be activated or replaced with a new electrode. If the response time of the measurement buffer is very short, but the measured sample is unstable, it means that the electrode is not suitable for measuring the measured sample. Please select a suitable electrode according to the electrode selection guide.
11. The sample temperature is 10°C. At this time, the meter displays the pH value at 10°C or 25°C
Answer: The acidity meter shows the pH value of the solution at the current temperature; if it is measured at 10°C, the meter displays the value of the solution at 10°C; if it is necessary to obtain a pH of 25°C, the temperature of the solution must be raised/lowered to 25°C , and then measure. The temperature compensation of the acidity meter refers to compensating the influence of temperature on the pH electrode, but it cannot compensate the pH value at any temperature to 25°C.
